210 TllH A.MKKICAX MONTHLY |.Tnly, 



in A TOMS. 



Cultivation of Diatoms. — Dr. L. Mnccliiali, in :i cDiiiiimnica- 

 tion lo till' Ji'iirnul de Mirnxfraphie, points out thut tliiitoins iirc 

 ca.'sily fultivatt'tl in the nutritive solution used in vcgtliiUle 

 physiology, iirovitieti tliat a few drops of silicate of )»otash be 

 added to the medium. Or, the very water which the diatoms 

 inhahit may he used. This when (iltered. and with the addi- 

 tion of a few drops of strong silicate of potash solution, forms 

 nn excellent fluid. The medium placed in a watch-glass is 

 then inoculated with a loo]iful of the water iidiabited hy the 

 diatoms, and the two fluids having Ix-en tiioroughly niix-^d 

 togetlicr hy stirring, a loopful of the mi.xture is jdaced on the 

 surface of a cover-glass; the exact thickness is ))reviously ascer- 

 tained. To the margin of a cavity of a hollow-grt)un(l slide is 

 then applied (?ome vjiseline, and this is carefully pi iced over 

 the cover-glass. The slide, now containing a hanging-droji 

 cultivation, is turned over. In such a drop the diatoms are in 

 an almost natural state, and their development and mode of 

 life may he watched under a power as high as 1-18, though the 

 lens commonly em|)loyed hy the author is a dry apochromatic 

 with focal distance of 4 mm. and N. A. 0.95. In combination 

 with eye-pieces 6, 12, and 18, magnifications of 372, 750, and 1, 

 125 were obtained. The best ])art for oi^serving the diatoms is 

 the edge of the droj), and this should he first centered under a 

 low power. — Engluh Mechanic. 



MICROSCOPICAL SOCIETIES. 



Calcutta, India. 



7%« year 1892. — Number of Members, 81, an increase of 8. 

 Receipts 8200; Expenses 8125; Balance on hand, December 31, 

 875. The Fifth Annual Report '7 pj).) was issued in January, 

 189o. Ten papers were read during 1892, as follows : 



By J. Wood-Ma.son, (1) on the Stridulating organs in one of 

 the Myriapods, (2j an elementary account of the Protozoa. 



By W. J. Simmon-*, (\) on diatoms from Hungary, (2) the eye 

 of Erislalis tenax, (Z) on Hyaline .Spherules found in cerrace- 

 dust. 



